”All honor to Allah! On August 17, our efforts let us execute the sabotage attack on Russia’s biggest Hydro Electric plant. We had been working on it for a long time and it was thoroughly thought out,” the statement on the website says.

”We managed to put a clock-operated antitank bomb in the plant’s main generator hall. The damage the blast brought turned even greater than we had planned. It resulted in the complete halt of the plant’s functioning and cost Russia billions of dollars.”

The terrorists’ claims come as a surprise as Russia’s prosecutor’s office hadn’t considered the possibility of a terrorist act while investigating the case.

The country’s emergency ministry says there was no explosive residue left on the site.

The Kremlin refused to comment on the issue, calling the claims “idiotic”, Reuters reports.